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livetrax/scripts/midigenerator.lua

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ardour {
["type"] = "dsp",
name = "Midi Generator",
category = "Example", -- "Utility"
license = "MIT",
author = "Ardour Lua Task Force",
description = [[An Example Midi Generator for prototyping.]]
}
function dsp_ioconfig ()
return { { midi_out = 1, audio_in = 0, audio_out = 0}, }
end
local tme = 0 -- sample-counter
local seq = 1 -- sequence-step
local spb = 0 -- samples per beat
local midi_sequence = {
{ 0x90, 64, 127 },
{ 0x80, 64, 0 },
}
function dsp_init (rate)
local bpm = 120
spb = rate * 60 / bpm
if spb < 2 then spb = 2 end
end
function dsp_run (_, _, n_samples)
assert (type(midiout) == "table")
assert (spb > 1)
local m = 1
for time = 1,n_samples do -- not very efficient
-- TODO, timestamp the sequence in beats, calc/skip to next event
tme = tme + 1
if tme >= spb then
midiout[m] = {}
midiout[m]["time"] = time
midiout[m]["data"] = midi_sequence[seq]
tme = 0
m = m + 1
if seq == #midi_sequence then seq = 1 else seq = seq + 1 end
end
end
end